Biochemical characterization of a medaka (Oryzias latipes) orthologue for mammalian Factor XIII and establishment of a gene‐edited mutant

At the final process of blood coagulation, fibrin molecules are stabilized via a catalytic reaction by Factor XIIIA (FXIIIA), one of the family members of transglutaminase (TGase) that catalyzes protein cross-linking reactions. In this study, we characterized the orthologue of this enzyme in medaka (Oryzias latipes), an established model fish in which a coagulation system is also preserved. The recombinant protein of this orthologue enzyme was produced in baculovirus-infected insect cells and used for biochemical property analysis including activation by thrombin-proteolysis and calcium-dependence of the TGase enzymatic activity. Immunostaining and immunoblotting revealed that medaka FXIIIA is expressed in the kidney, bone and esophagus in addition to blood cells. Furthermore, the gene-mutant fish was established using the CRISPR/Cas9 system. The loss of FXIIIA expression was validated in the mutants, and phenotypes, such as absence of fibrin cross-linking, were investigated in the established fish. This article is protected by copyright. All rights reserved.